Suction roll assembly for cleaning felts

ABSTRACT

A honeycomb roll is rotatably mounted on a fixed suction pipe to serve as a carrier for a detergent wetted press felt of a papermaking machine, there being sealing strips operable from outside the roll to form a narrow suction slot conduit between the outside of the pipe and the inside of the honeycomb roll. An end seal wall, having a split, sealing insert, located between the sealing strips also moves axially to form deckle means. Each sealing strip includes cam means permitting independent sealing adjustment on each side of the slot.

United States Patent [72] Inventors Edward T. Bryand 2,290,777 7/1942 Street 162/371 South Portland; 3,100,928 8/1963 Bryand... 162/369 X Edward G. Peabody, Gotham, both of 1,812,812 6/1931 Street 162/371 1 N 1112 3,201,308 8/1965 Goddard etal. 162/374 x gfg 16 1969 Primary Examiner-S. Leon Bashore [45 1 Patented Dec. 1971 :ssistanl Egaminerz'lghomas G. Scavone 73 Assignee Metal-Tech Inc. mmey Biddleiord, Maine ABSTRACT: A honeycomb roll is rotatably mounted on a [54] SUCTION ROLL ASSEMBLY FOR CLEANING fixed suction pipe to serve as a carrier for a detergent wetted FELTS press felt of a papermaking machine, there being sealing strips 1 Claim Drawn. H s operable from outside the roll to form a narrow suction slot g g conduit between the outside of the pipe and the inside of the [5 2] [1.5. CI 162/371, honeycomb roll. An end seal wall, having a split, sealing insert, 162/274, 162/279, 162/368, 162/372 located between the sealing strips also moves axially to form [51] lnt.Cl D2lf 3/10 deckle eans. Each sealing strip includes cam means per- [50] Field oi Search 162/369-371; mitting independent sealing adjustment on each side of the 277/154 slot.

[56] References Cited UNITED STATES PATENTS RE|6.848 1/1928 Berry 162/369 2 40 s9 81 s; 33 so 3 4 8 67 47 6 6 6 87 9 4! 44 79 44 i t mm m IHYI INVENTOR. EDWARD T. BRYAND BY EDWARD G. PEABODY W f-W A TTORNEYJ SUCTION ROLL ASSEMBLY FOR CLEANING FELTS BACKGROUND OF THE INVENTION Suction boxes and suction rolls have long been known in the papermaking art, the roll having a perforated cylindrical'face and hollow journals or the roll being a sleeve rotatable on bearings carried by a stationary suction pipe.

Honeycomb openwork, formed of thin metal strips bent to half-hexagonal shape, such as shown in my U.S. Pat. Nos. 3,139,375 of June 30, 1964, and No. 3,259,961 of July 12, 1966, has heretofore been used as a dryer roll mounted on a blow pipe. A deckle, or valve, control system for such dryer rolls is disclosed and claimed in copending application, Ser. No. 802,362 of Feb. 26, 1969.

In the prior art, honeycomb cell strips have been used ,as edge seals engaging the inner face of the honeycomb roll, as taught in the said U.S. Pat. No. 3,139,375, and dependence on the close fit of the inner face of the roll on the outside of the pipe for edge sealing is disclosed in the said copending application. However, it has been found that a better seal is necessary along the edges of the suction box, or pipe, within the roll, when it is necessary to condition, or clean, a papermaking felt. This is for the reason that such felts, especially in the first press section of a Fourdrinier machine, plug up with fibers and fillers, and must be washed on the rear face witha shower of detergent, and the detergent, fibers and fillers must be removed before the return stretch reaches the paper web.

In order to successfully use a honeycomb openwork roll, with its 90 percent or more open area, as a suction roll, for drawing detergents, fibers and fillers from the front of a felt through the felt and away from the back, an intense, high suction is required, which in turn requires tight sealing without scuffing of the roll. It will be understood that the roll is freely rotatable to travel at the same surface speed as the felt, but that if the seal pressure, or friction, slows or stops the roll, the felt will be scuffed and damaged.

SUMMARY OF THE INVENTION In this invention the suction box, or slotlike conduit between the pressure pipe and the roll, is formed by two pairs of parallel flanges, each on an opposite side of the suction apertures. An elongated metal, or plastic, sealing strip is slidably seated between the flanges of each pair and provided with spaced cam tracks, each riding on a cam roll. Thus when each strip is moved a slight distance axially, it is caused to move outwardly at spaced distances throughout its length, to firmly press its outer edge into sealing engagement with the inner face of the roll. Sealing pressure is uniform all along the length of the slot and can be adjusted from outside the pipe to be just sufficient to seal without slowing the roll. An end wall seal is also provided which not only moves outwardly but also moves axially a short distance to serve as a deckle for conforming to various selvedge widths in a limited range of 2 or 3 inches.

DRAWING FIG. 1 is a front elevation of a felt-conditioning roll assembly of the invention, with parts broken away;

FIG. 2 is a section on line 2--2 of FIG. 1;

FIG. 3 is a fragmentary view of the end wall of the invention; and

FIG. 4 is a diagrammatic side elevation of a typical press felt-conditioning system including the roll of this invention.

As best shown in FIG. 4 of the drawing, the first press section of a papermaking machine of the Fourdrinier type includes the first press roll 21, guide rolls 22, 23, 24, and 25, and a stretch roll 26, the endless felt 27 being trained therearound in the usual manner. The front face 28 of felt 27 contacts the paper fibers, fillers and pulp stock so that it tends to plug up in the interstices of the woven felt. An oscillating detergent shower 29 is applied to the rear face 30 of the felt, for the purfiber, from which the felt 27 is woven, must be carefully handled to avoid its marking the paper and it has a tendency to shrink or pull in any zone in which it is more wet, or dry, than in another zone.

In FIG. 4, the woven fiber of the felt 27 having been saturated with detergent liquid at shower 29 and bent back and forth as it travels around rolls 26, 23 and 25, is again bent out .of its normal plane to pass over the felt-conditioning roll asannular space 48 therebetween. Thus there is no frictional contact between the faces 46 and 47 and no need for careful machining of face 46.

The elongated stationary fluid pressure pipe 42 is provided with an elongated row 49 of fluid apertures 50, the row 49 extending axially along face 46, from one end 51 of the pipe to the other end 52. Since roll 39 is to be used as a suction roll and is intended to apply negative pressure to the rear face 30 of felt 27 in an amount three or four times greater than is conventional with suction boxes, or with traversing vacuum boxes, the apertures 50 are relatively small, for example, 1 inch in diameter. The suction source 53, connected to the right angular conduit 54 of pipe 42, may be mill suction but is preferably a separate source capable of creating a vacuum of 15 inches of mercury or more to enable the roll to handle large volumes of liquid.

Sealing means 58 is provided in the annular space 48 to form a narrow suction slot conduit, or throat, between the row 49 of perforations 50 and the inside face 47 of roll 39. Sealing means 58 includes imperforate wall means 59 outstanding from the pipe 42 on each opposite side of row 49, preferably in the form of two pairs 60 and 61 of parallel flanges, such as 62 and 63, preferably integral with pipe 42. The pairs of flanges 60 and 61 may be in parallelism, especially when the space 64 therebetween is narrow, or they may be radial, the advantage of parallelism being the ease of sliding an end seal therebetween without leakage.

Extending transversely of the spaces 64 between each pair of flanges 62 and 63, and at spaced axial distances therealong, are cam rollers, such as 66, and seated in each space 64 is an elongated sealing strip 67, of metal or plastic, having axially spaced cam tracks 68, each cooperable with a set of rollers 66. The outer edges 69 of the flanges terminate just short of the inner face 47 of the roll and the outer edge 70 of each strip 67 is curved to contact, and seal, with the rotating face 47 without damaging the same or causing scuffing.

Each sealing strip 67 includes a bracket 73 extending through a slot 74 in pipe 42 and pivotally connected at 75 to actuating means 76 in the form of a rod such as rod 77 or 79 extending outside the end 50 of pipe 42 and adjustable by the turn nuts such as 78, or other suitable means. By turning a nut 78 a rod 77 or 79 is moved so that one or the other sealing strip 67 is raised or lowered in the flanges to a precise location for maximum sealing with minimum friction.

End seal means 80 is provided, and includes a sealing strip 81 mounted on a bracket 82, in the space 83 between the pair of flanges and normally in contact with inner face 47 of roll 39. Radial movement is not essential for this seal because of the small area it covers, but axial movement is desirable to form an edge deckle. As shown, the bracket 82 extends through a slot 84 in pipe 42 and is connected by a rod 85 to a threaded nut 86 so that it can be moved axially in a limited range of 2 or 3 inches to conform to selvedge widths of web 27. A nut 86a and rod 87 similarly moves the bracket 82a and strip 81a at the other end of the roll.

As shown in FIG. 3, when the space 83 between the pairs of flanges is relatively wide, the end seal strip 81, preferably includes a slot 88 in the curved outer edge 89, in which an arcuate, plastic seal 90 is radially slidable while guided on pins such as 91. Threaded means, preferably set screws 92, may be used to raise and lower seal 90 into contact with inner face 47 while the end seal 81 continues to be axially movable on a deckle. Preferably the plastic seal 90 is formed in two blocks 93 and 94, which overlap as shown at the split 95, so that if the space 83 is of tapered section, the seal can expand as it moves outwardly without leakage of suction.

What is claimed is:

1. In a honeycomb roll assembly of the type having an elongated, stationary fluid pressure pipe with an elongated, axial fluid aperture therein, a hollow cylindrical honeycomb openwork roll mounted on axially spaced bearings to rotate around said pipe, and an annular space between the inner face of said roll and the outer face of said pipe, the combination of:

sealing means in said annular space for forming a narrow suction slot conduit between said roll and the apertures in said pipe, said means including:

imperforate wall means outstanding from said pipe on each opposite side of the axial fluid aperture therein, said wall means extending in parallelism nearly to the inner face of said roll;

a pair of sealing strip means, each coextensive in length with said wall means, and supported therein for sliding movement in a generally radial direction,

actuating means, extending from outside of one end of said pipe and connected to each said sealing strip means, for moving each said strip independently of the other in and out of contact with the inside face of said roll to form a seal therewith, and

end seal means, at each opposite end of said annular space for sealing the ends of the slot formed by said sealing strip means said end seal means including a curved outer edge having a slot therein, a radially movable, split, sealing strip insert slidably seated in said slot and threaded means for affixing said split insert at desired heights in said slot. 

